The monitoring of blood glucose concentrations is an essential part of the daily routine of diabetics. The blood glucose concentration has to be determined quickly and simply several times a day in order, if appropriate, to be able to take suitable medical measures. So as not to restrict the diabetic's daily routine any more than is necessary, suitable portable devices are often employed which are intended to be easy to carry around and to operate, such that the blood glucose concentration can be measured, for example, at the workplace or even during leisure time.
Various portable devices are presently available on the market, some of them functioning according to different measurement methods. Various diagnostic methods are used in these devices, for example optical or even electrochemical measurement methods. One example of a frequently used measurement method makes use of a special kind of electrochemical test strip. These test strips are, for example, configured in such a way that a predetermined quantity of blood is conveyed to an electrode system via a capillary system in the test strip. For modem test strips, a quantity of blood of ca. 1.5 μl is sufficient; sometimes even quantities of blood of less than 1 μl. The electrode system may, for example, involve gold electrodes that are provided with a coating. The coating contains at least different enzymes and so-called mediators and has the effect that charge carriers (for example in the form of redox molecules) form within the sample on the electrodes, the concentration of these charge carriers being dependent on the blood glucose concentration. The concentration of these charge carriers can be determined by means of the gold electrodes and a suitable measurement system, for example by means of a current-voltage measurement, and from this concentration it is possible, finally, to calculate the blood glucose concentration.
An important element of these diagnostic systems is therefore represented by the corresponding test strips. Typically, about 5 to 7 such test strips are needed each day by a diabetic. It is essential that the test strips are kept clean and dry, in order to ensure that the measurement of the blood glucose concentration is not rendered inaccurate by their contamination or by the action of moisture.
However, a problem that often arises is that the user or patient does not correctly close a test strip container for test strips after he or she has removed one or more test strips. It can also happen that the test strip container is not closed at all for quite a long time. The resulting lack of a tight seal and the effect of air on the test strips can lead to a deterioration in the quality of the test strips and to false measurement results.
A further problem with the test strips is that the properties of the test strips used may often vary from batch to batch. This leads to in some cases huge variations in the accuracy of the blood glucose concentration measurement. In many known commercial systems, batch information relating to the test strips therefore has to be input into an analysis module prior to a corresponding blood glucose concentration measurement, so that the analysis module can correctly “interpret” the measurement data of the test strip by means of this batch information, in order to determine a correct blood glucose concentration from said data. There are several known methods for inputting the batch information into the analysis module. For example, it is possible here to use suitable barcodes which, for example, are arranged on the test strip container and can be read out by the analysis module. Alternatively, systems are also known in which a data carrier, often also called a ROM key, is attached to the test strip container holding the test strips. This data carrier can, for example, be attached loosely to the closed test strip container for the test strips, or it can also be integrated fixedly into the test strip container. However, if this ROM key is lost (for example by its coming loose from the test strip container), then the batch information is also lost along with it, and the test strips are therefore by and large unusable.
Moreover, the known ways of transmitting batch information into the analysis module have the disadvantage that they presuppose a corresponding action on the part of the user or patient. Automatic transmission of batch information does not take place. However, if the user or patient forgets to transmit this batch information, or if an error occurs when transmitting the batch information, this can have the consequence, for example, of the blood glucose concentrations being calculated incorrectly. This may cause incorrect medical counter-measures to be taken, for example in the form of incorrect dosages of insulin, which can have adverse consequences for the patient.
EP 0 101 812 B1, also published as U.S. Pat. No. 4,419,016 discloses a device for presentation of medicaments, in which a medicament is dispensed from a container that comprises a cap, and a sensor device records when the cap of the container is opened. The container also comprises a clock which records the times at which the cap is opened or closed. A device and display are also provided which notify a patient when a medicament has to be taken again.
From the field of pharmacy, several systems are known in which pharmaceutical products are traced by means of what are known as radio frequency identification (RFID) tags. Such a system is known from WO 03/071943, also published as U.S. Pat. No. 7,175,081 B2, for example. In the arrangement described in the latter, medicinal products are provided with RFID tags and stored in a suitable storage cabinet. A receiver device, which is coupled to a corresponding processor, receives the signals from the RFID tags of the medicinal products and can, for example, automatically organize the management of these products.